The brain noradrenergic system supplies the neurotransmitter norepinephrine throughout the brain via widespread efferent projections, and plays a pivotal role in modulating cognitive activities in the cortex. Profound noradrenergic degeneration in Alzheimer's disease (AD) patients has been observed for decades, with recent research suggesting that the locus coeruleus (where noradrenergic neurons are mainly located) is a predominant site where AD-related pathology begins. Mounting evidence indicates that the loss of noradrenergic innervation greatly exacerbates AD pathogenesis and progression, although the precise roles of noradrenergic components in AD pathogenesis remain unclear. The aim of this review is to summarize current findings on noradrenergic dysfunction in AD, as well as to point out deficiencies in our knowledge where more research is needed.

Myofibroblasts are effector cells in fibrotic disorders that synthesize and remodel the extracellular matrix (ECM). This study investigated the role of the Src kinase pathway in myofibroblast activation in vitro and fibrogenesis in vivo. The profibrotic cytokine, transforming growth factor b1 (TGF-b1), induced rapid activation of Src kinase, which led to myofibroblast differentiation of human lung fibroblasts. The Src kinase inhibitor AZD0530 (saracatinib) blocked TGF-b1-induced Src kinase activation in a dose-dependent manner. Inhibition of Src kinase significantly reduced a-smooth muscle actin (a-SMA) expression, a marker of myofibroblast differentiation, in TGFb1-treated lung fibroblasts. In addition, the induced expression of collagen and fibronectin and three-dimensional collagen gel contraction were also significantly inhibited in AZD0530-treated fibroblasts. The therapeutic efficiency of Src kinase inhibition in vivo was tested in the bleomycin murine lung fibrosis model. Src kinase activation and collagen accumulation were significantly reduced in the lungs of AZD0530-treated mice when compared with controls. Furthermore, the total fibrotic area and expression of a-SMA and ECM proteins were significantly decreased in lungs of AZD0530-treated mice. These results indicate that Src kinase promotes myofibroblast differentiation and activation of lung fibroblasts. Additionally, these studies provide proof-ofconcept for targeting the noncanonical TGF-b signaling pathway involving Src kinase as an effective therapeutic strategy for lung fibrosis.

Understanding the underlying molecular mechanisms of liver fibrosis is important to develop effective therapy. Herein, we show that focal-adhesion-kinse (FAK) plays a key role in promoting hepatic stellate cells (HSCs) activation in vitro and liver fibrosis progression in vivo. FAK activation is associated with increased expression of α-smooth muscle actin (α-SMA) and collagen in fibrotic live tissues. Transforming growth factor beta-1 (TGF-β1) induces FAK activation in a time and dose dependent manner. FAK activation precedes the α-SMA expression in HSCs. Inhibition of FAK activation blocks the α-SMA and collagen expression, and inhibits the formation of stress fibers in TGF-β1 treated HSCs. Furthermore, inhibition of FAK activation significantly reduces HSC migration and small GTPase activation, and induces apoptotic signaling in TGF-β1 treated HSCs. Importantly, FAK inhibitor attenuates liver fibrosis in vivo and significantly reduces collagen and α-SMA expression in an animal model of liver fibrosis. These data demonstrate that FAK plays an essential role in HSC activation and liver fibrosis progression, and FAK signaling pathway could be a potential target for liver fibrosis.

Accumulation of amyloid β (Aβ) peptides in the brain is the key pathogenic factor driving Alzheimer's disease (AD). Endocytic sorting of amyloid precursor protein (APP) mediated by the vacuolar protein sorting (Vps10) family of receptors plays a decisive role in controlling the outcome of APP proteolytic processing and Aβ generation. Here we report for the first time to our knowledge that this process is regulated by a G protein-coupled receptor, the α 2A adrenergic receptor (α 2A AR). Genetic deficiency of the α 2A AR significantly reduces, whereas stimulation of this receptor enhances, Aβ generation and AD-related pathology. Activation of α 2A AR signaling disrupts APP interaction with a Vps10 family receptor, sorting-related receptor with A repeat (SorLA), in cells and in the mouse brain. As a consequence, activation of α 2A AR reduces Golgi localization of APP and concurrently promotes APP distribution in endosomes and cleavage by β secretase. The α 2A AR is a key component of the brain noradrenergic system. Profound noradrenergic dysfunction occurs consistently in patients at the early stages of AD. α 2A AR-promoted Aβ generation provides a novel mechanism underlying the connection between noradrenergic dysfunction and AD. Our study also suggests α 2A AR as a previously unappreciated therapeutic target for AD. Significantly, pharmacological blockade of the α 2A AR by a clinically used antagonist reduces AD-related pathology and ameliorates cognitive deficits in an AD transgenic model, suggesting that repurposing clinical α 2 AR antagonists would be an effective therapeutic strategy for AD.adrenergic receptor | amyloid | processing | SorLA | sorting E xcess amyloid β (Aβ) peptides in the brain are a neuropathological hallmark of Alzheimer's disease (AD) and are generally accepted as the key pathogenic factor of the disease (1). Aβ is generated by two sequential cleavages of amyloid precursor protein (APP) by β and γ secretase, whereas cleavage by α secretase within the Aβ domain precludes Aβ generation (2, 3). APP and the secretases undergo endocytic sorting into various organelles, such as the trans-Golgi network, the plasma membrane, and endosomes (2-6). The initial step of APP processing by α versus β secretase preferentially occurs in distinct compartments of the cell. Although α secretase-mediated cleavage of APP occurs on the plasma membrane, β secretase primarily interacts with and cleaves APP in endosomes (2-6). Therefore, endocytic sorting of APP into different membranous compartments, causing it to coreside or avoid a particular secretase, plays a decisive role in APP proteolytic processing. Consistent with this notion, abnormalities of the endocytic pathway have been found to precede Aβ deposition in late-onset AD (7).Retrograde sorting of APP from endosomes to trans-Golgi network mediated by the vacuolar protein sorting-10 (Vps10) family proteins and the retromer complex represents a critical mechanism to prevent amyloidogenic processing of APP (8-10) and has recently emerged as a potential targe...

S100A4 expression is associated with poor clinical outcomes of patients with pancreatic cancer. The effects of loss or gain of S100A4 were examined in pancreatic cancer cell lines. S100A4 downregulation remarkably reduces cell migration and invasion, inhibits proliferation, and induces apoptosis in pancreatic tumor cells. S100A4 downregulation results in significant cell growth inhibition and apoptosis in response to TGF-b1, supporting a non-canonical role of S100A4 in pancreatic cancer. The role of S100A4 in tumor progression was studied by using an orthotopic human pancreatic cancer xenograft mouse model. Tumor mass is remarkably decreased in animals injected with S100A4-deficient pancreatic tumor cells. P27 Kip1 expression and cleaved caspase-3 are increased, while cyclin E expression is decreased, in S100A4-deficient pancreatic tumors in vivo. S100A4-deficient tumors have lower expression of vascular endothelial growth factor, suggesting reduced angiogenesis. Biochemical assays revealed that S100A4 activates Src and focal adhesion kinase (FAK) signaling events, and inhibition of both kinases is required to maximally block the tumorigenic potential of pancreatic cancer cells. These findings support that S100A4 plays an important role in pancreatic cancer progression in vivo and S100A4 promotes tumorigenic phenotypes of pancreatic cancer cells through the Src-FAK mediated dual signaling pathway. S 100A4, also known as metastasin (Mts1) 1,2 , belongs to the S100 family, and it is a calcium-binding protein with two EF-hands 3-5 . S100A4 is involved in a variety of physiological functions, such as cell motility, adhesion, proliferation, invasion, and metastasis 3,4,6,15 . S100A4 is considered as a mediator of tumor progression and metastasis 3,6 . S100A4 can suppress the BNIP3 expression and contributes to chemoresistance and survival in pancreatic cancer cells 16 . S100A4 is involved in epithelial mesenchymal transition mediated by the Shh-Gli1 signaling pathway 17 , and S100A4 promotes cell invasion in pancreatic cancer cells 18 . S100A4 is overexpressed in pancreatic cancer 7 , and is also frequently overexpressed in other metastatic cancers, including prostate 8,9 , ovarian 10 , and breast carcinomas 11,12 . Increased S100A4 expression has been strongly associated with poor clinical outcomes of the pancreatic cancer 7,13,14 . Although aberrant S100A4 expression is an independent biomarker of poor outcome, the molecular mechanisms by which S100A4 regulates pancreatic cancer progression in vivo are not completely understood. Whether S100A4 directly contributes to pancreatic cancer progression in vivo or is just a secondary effect of other changes during pancreatic cancer progression remains to be answered.Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase, that is upregulated in many types of cancers, including pancreatic cancers 19,20 . FAK is activated when its tyrosine-397 (Y397) is phosphorylated, and maximal FAK activation requires binding of Src kinase 21,22 . Increased FAK activation is posit...

Dengue disease is becoming a huge public health concern around the world as more than one-third of the world's population living in areas at risk of infection. In an effort to assess host factors interacting with dengue virus, we identified claudin-1, a major tight junction component, as an essential cell surface protein for dengue virus entry. When claudin-1 was knocked down in Huh 7.5 cells via shRNA, the amount of dengue virus entering host cells was reduced. Consequently, the progeny virus productions were decreased and dengue virus-induced CPE was prevented. Furthermore, restoring the expression of claudin-1 in the knockdown cells facilitated dengue virus entry. The interaction between claudin-1 and dengue viral prM protein was further demonstrated using the pull-down assay. Deletion of the extracellular loop 1 (ECL1) of claudin-1 abolished such interaction, so did point mutations C54A, C64A and I32M on ECL1. These results suggest that the interaction between viral protein prM and host protein claudin-1 was essential for dengue entry. Since host and viral factors involved in virus entry are promising therapeutic targets, determining the essential role of claudin-1 could lead to the discovery of entry inhibitors with attractive therapeutic potential against dengue disease.

TGF-b1 induces an increase in paracellular permeability and actin stress fiber formation in lung microvascular endothelial and alveolar epithelial cells via small Rho GTPase. The molecular mechanism involved is not fully understood. Neuronal Wiskott-Aldrich syndrome protein (N-WASP) has an essential role in actin structure dynamics. We hypothesized that N-WASP plays a critical role in these TGF-b1-induced responses. In these cell monolayers, we demonstrated that N-WASP down-regulation by short hairpin RNA prevented TGF-b1-mediated disruption of the cortical actin structure, actin stress filament formation, and increased permeability. Furthermore, N-WASP down-regulation blocked TGF-b1 activation mediated by IL-1b in alveolar epithelial cells, which requires actin stress fiber formation. Control short hairpin RNA had no effect on these TGF-b1-induced responses. TGF-b1-induced phosphorylation of Y256 of N-WASP via activation of small Rho GTPase and focal adhesion kinase mediates TGF-b1-induced paracellular permeability and actin cytoskeleton dynamics. In vivo, compared with controls, N-WASP down-regulation increases survival and prevents lung edema in mice induced by bleomycin exposure-a lung injury model in which TGF-b1 plays a critical role. Our data indicate that N-WASP plays a crucial role in the development of TGF-b1-mediated acute lung injury by promoting pulmonary edema via regulation of actin cytoskeleton

The emergence and spread of multidrug-resistant Plasmodium falciparum and recent detection of potential artemisinin-resistant strains in Southeast Asia highlight the importance of developing novel antimalarial therapies. Using a previously generated stable transgenic P. falciparum line with high-level firefly luciferase expression, we report the adaptation, miniaturization, optimization, and validation of a highthroughput screening assay in 384-well plates. Assay conditions, including the percentage of parasitemia and hematocrit, were optimized. Parameters of assay robustness, including Z 0 -value, coefficient variation (CV), and signal-to-background (S/B) ratio, were determined. The LOPAC 1280 small-compound library was used to validate this assay. Our results demonstrated that this assay is robust and reliable, with an average Z 0 -value of >0.7 and CV of <10%. Moreover, this assay showed a very low background, with the S/B ratio up to 71. Further, identified hits were selected and confirmed using a SYBR Green I-based confirmatory assay. It is evident that this assay is suitable for large-scale screening of chemical libraries for antimalarial drug discovery.